I generally don’t wait till price is at the top of the range but will start shorting in top 1/3 and covering the middle third or bottom third depending on how price is moving. Waiting to cover a short at the very bottom of the range every time is not a realistic strategy but sometimes will work out ok. For longs buy in bottom 1/3 and buy more if price moves against me. Then exit in middle or top 1/3. Basically the idea is catch a slice out of the middle of the range. So the range has to be at least 3 times as broad as a min scalp with I consider to be 1 pt in the ES.